BU 5000/320 Power Supply Project

1. Introduction

The book "Power supply system" of the project "Power supply of the BU drilling rig 4500/270 ECBMCH No. 14805" was developed in accordance with the design specification issued by the NF LLC RNBurenie.

The project provides for:

Power supply of the drilling rig for 6kV voltage, including temporary VL6kV, input high-voltage cell 6kV, cable (air) line 6 kV from this cell to KRU1 of the drilling rig;

Power supply to the loads of the drilling rig with voltage of 0.4kV, as well as to the residential shift camp and brigade farm with cable lines;

Power supply of drilling rigs operating in emergency response mode and in post-accident mode from own emergency power supply source;

Lightning protection and grounding of the bush site process units during the drilling period.

This project considers the temporary power supply of the BU 4500/270 ECBMCH plant No. 14805.

The power sources of the drilling rig are the existing 110/35/6 kV (35/6kV) PS or an independent power source based on diesel power plants of appropriate capacity.

Temporary power supply of the designed drilling rig is made according to the temporary 6 kV HF.

In this project four options of drilling rig power supply are considered:

Connection of BU 4500/270 ECBMH drilling rig from main VL6kV, option 1.

Connection of BU 4500/270 ECBMH drilling rig from main VL6kV, variant 2.

Connection of BU 4500/270 ECBMH drilling rig from main VL6kV, option 3.

Connection of BP 4500/270 ECBMH drilling rig from BKRU6 kV

Connection of BP 4500/270 ECBMH drilling rig from 35/6 kV PS

Connection of BU 4500/270 ECBMH drilling rig from DGP (1 arrangement variant).

Connection of BU 4500/270 ECBMH drilling rig from DGP (2 arrangement variant).

Connection of BU 4500/270 ECBMH drilling rig from DGP (3 arrangement variant).

Electricity consumers. Electrical loads and power consumption

2.1 Electric Power Consumers

The main electric receivers of the bush site are:

- equipment of drilling rig and tower structures;

- consumers of brigade economy and residential town.

2.2 Category of consumers by reliability of power supply

Electric consumers of the drilling rig of the bush of oil producing wells are classified as III category in terms of reliability of power supply. The drilling rig is powered by:

- from the existing MS 110/35/6kV (MS 35/6kV);

- from independent power supply source based on diesel power plants.

Power supply of category III consumers can be performed from one power supply, provided that the power supply interruptions required for repair or replacement of the damaged component of the power supply system do not exceed one day (Item 1.2.21 PUE).

For emergency situations, power supply of 0.4kV consumers is carried out from emergency DPS with capacity of 315kW.

2.3 Power Quality Requirements

In accordance with GOST 13109:

- Values of steady-state voltage deviation ∆Uy shall not exceed 5% and 10% of the rated voltage of the electrical network in normal and post-accident modes of the network operation, respectively.

- Values of sinusoidity distortion coefficient of voltage curve for 6kV network shall not exceed 8%.

-The values of the non-symmetry coefficient of voltages in the reverse sequence at the points of common connection to electrical networks should not exceed 4%.

- Values of frequency deviation shall not exceed 0.2 and 0.4 Hz from nominal frequency of electric network in normal and post-accident modes of network operation, respectively.

The decisions taken in the draft on the construction of electric networks and the selection of the section of overhead power transmission lines wires ensure the fulfillment of the requirements of GOST 13109 for electricity quality indicators. Distortions of current curve and voltage introduced by frequency converters of drive motors do not exceed 4% of the value of the main harmonic component.

Before putting the facility into operation, it is necessary to perform commissioning of electrical devices in accordance with SNiP 3.05.0685 "Electrical devices."

Grounding and lightning protection

The grounding of the temporary VL6kV is made by the grounding device of each separate metal support. The ground electrodes from the tubing string ∅50mm length 3m, are buried in the ground to a depth of 3.5m and are connected to each other by strip steel 40x5mm or steel round conductor ∅12mm.

Connection of vertical and horizontal earthing electrodes is performed by overlapping welding.

Supports installed along process connections are grounded by connection to racks of cable rack or to grounding conductors connecting racks of cable rack, by two grounding conductors, by overlapping welding with weld length D = 6 mm according to GOST 526480.

VL supports and racks of cable rack are connected to vertical grounding conductor by means of strip steel 40x5mm or steel round conductor ∅12mm.

The grounding device for the drilling rig is a grounding circuit laid in the ground at a depth of (0.50.7m), consisting of tubing string ∅50mm with a length of 3 m, buried in the ground to a depth of 3.5m and welded together by strip steel section. 40x5mm or a steel circular conductor ∅12mm in a continuous electrical network. Horizontal grounding trenches shall be filled with homogeneous soil free of crushed stone and construction debris. Depth of horizontal grounding conductors laying is not less than (0.50.7 m). The lower depth of the gasket is allowed at the places of their connections to the equipment, when entering buildings and in the areas of permafrost soils. Grounding or trailing lines and branches from them in outdoor installations shall be accessible for inspection.

After drilling the "conductor" of the first well, the grounding of the VU is performed by connecting the grounding circuit to the lowered casing. Resistance of grounding device of drilling rig not more than - 2 Ohm for drilling rigs equipped with power upper drive with transformer TSZP1000 800kVA 6000/690V

This grounding device provides protection against both direct lightning strikes and high potential drift, against static electricity.

Ground all metal structures of the cable rack by connecting them to each other and to the grounding devices of the drilling rig and re-grounding circuits of the process equipment units and the residential area.

Process equipment units and residential building shall be connected to grounding loop in two places using strip steel 40x5mm or steel round conductor ∅12mm.

Connect the open conductive parts, refer to para 1.7.76 of PUE, to the de-grounded neutral of the power supply.

All metal parts of electrical installations that are not normally energized shall be occupied by connection with zero wire of 380/220V network. Electrical equipment shall be used as a separate core cable (PUE, para. 7.3.135).

Connections with grounding devices shall be made by overlapping welding with weld length D = 6 mm according to GOST 526480.

To protect people from electric shock in case of insulation damage, the following protection measures are provided for indirect touching:

Protective grounding;

Protective automatic power-off;

Potential equalization.

Type of grounding of power distribution system of electrical installations with voltage up to 1 kV according to GOST 50571.2 TNCS.

To perform automatic power-off, it is provided to coordinate the characteristics of the protective circuit breakers and the parameters of conductor protection, to ensure the normalized time of disconnection of the damaged circuit by the protective switching apparatus.

Potential equalization system is made by connection to main grounding bus and common grounding line:

PEN of feeder cable conductors;

Switchboard housings;

Metal pipes of process pipelines;

Grounding conductors;

Metal housings of the units.

All electrical installation works shall be performed in accordance with SNiP 3.05.0685 and PUE (6.7 ed.)

Lightning protection of drilling rig site facilities is performed in accordance with the "Instruction on lightning protection of buildings and structures" RD. 34.21.12287 Buildings and structures shall be protected against direct lightning strikes, high potential drifts and static electricity.

To protect buildings, structures and outdoor installations from direct lightning strikes and secondary manifestations of lightning, metal bodies of electrical devices are connected to the grounding device.

Электроснабжение буровых установок (БУ 5000-320).dwg